Bupu is a large male sable antelope with very dark brown fur. He has a brown-white underbelly, muzzle and marking just above his eyes and a black mane. He has dark blue eyes and a black nose. His inner ears are grey and light brown, with a black tip at the top. He has two long off-white horns. His tail has a black tuft at the end.
Bupu is a rather stubborn sable antelope who frowns at those who order him around. Whilst he may be eventually persuaded into taking orders, he does so begrudgingly, and will never hesitate to point out his frustration when he feels that he is being messed around. He is quick to give up, and difficult to work with at most times. Despite this, he appreciates politeness, and will gladly remove any hostility towards those who remember to be polite towards him.
After a rainstorm floods their grazing grounds, Bupu and his herd stand around in the water, waiting for it to pass. But when a second storm starts to brew, the Lion Guard, minus Beshte, rush to call them away for their own safety. Bupu refuses to leave, even after Ono warns him of the impending rain storm. When Fuli tells him to follow them, he still refuses, stating that they don't take orders from them. Kion understands that they are tired and hungry, but explains that, if they move, they'll have food and won't be standing around in water. Upon hearing this, Boboka talks with Bupu, urging him to reconsider their offer for the sake of the young ones. Reluctantly, he agrees, and the Guard escort them away across the side of a cliff.
The herd follow the Lion Guard around the side of a nearby cliff, until Kion warns them to get back. This annoys Bupu, having just been told to follow them. However, a minor rockslide then separates them. The Guard climb over the rocks, and Kion tries to get them to move. But Bupu refuses, stating that they are tired and 'give up'. The lion cub then walks towards the rocks, and Bunga assures him that Kion has got this, and for him to hold onto his antlers. Bupu irritably refutes his statement, informing him that they are horns. Before he can say anything else, Kion uses his Roar to blast the rocks out of the way. Proud of himself, Kion looks behind him and calls for them to follow again. Bupu refuses to move or even acknowledge him. Fuli then rushes up to Bupu, who claims they have come so far already. She is unimpressed, having glanced back the short distance they have traversed. This prompts Bupu to continue, albeit begrudgingly.
They arrive at the Flood Plains, where Bunga sends in Boboka and her son. Upon their leave, Bupu starts complaining again about how they were ordered around, criticizing the times when the Lion Guard had tried to help them. Fuli points out that they were all good reasons, when suddenly the rain storm breaks out. Eager to believe they'll be ordered to move out of the rain, Bupu informs them that they're not going anywhere. Fuli and Bunga are okay with this, since it's exactly what they want them to do anyway.
With the rain storm still going, Bupu resorts to more complaining. Fuli informs him that they'll tell them when to keep going, and asks him to stand and be quiet. Bupu suspires heavily and sits down. When Fuli orders him to stand up, Bupu isn't surprised that the Lion Guard is telling them what to do, causing the other sable antelopes to sit down in protest with him. Despite Fuli's best efforts, she is unable to get him to stand, even when Ono returns with the youngster. When Ono questions her actions, she explains what she's trying to do, only for Bupu to respond with 'Blah, blah, blah blah blah blah blah'.
Confirming that Beshte has finished the new Hippo Lane, Bunga then calls for them to 'follow that hippo', but Bupu remarks that it looks so wet. Fuli snaps and reminds them that they're already wet, and Bupu turns his head, telling her to continue yelling at them like they've done all day. Fuli has a change of heart, and apologizes for yelling. She goes on to say that it's been a long day for her as well as them, explaining how they can get something to eat on the other side. She returns to Bupu and asks them to go, adding 'please' at the end of her statement. To her surprise, Bupu responds by telling her that that was all they wanted to hear, and that it never hurts to be polite. He then calls for his herd to follow, and together, they run through the new Hippo Lane.
While running through the Flood Plains, they trample over Makuu's Float having been led there by Beshte and Basi. Bupu turns to Sable Antelope #1 and asks if he heard anything, but he responds with 'no' and they continue going.
Later, when the Flood Plains have cleared, Bupu and his herd can be seen grazing in the grass on the other side, finally safe.
As the leader of the Sable Antelope, Bupu attends the Savannah Summit with several other leaders and gets a surprise shock when Makuu gets invited too. Everyone travels to Mizimu Grove for the summit as the event begins, with Bupu warming up to some of the other guests.
Upon arrival, Bupu leaves for the Watering Hole, where he has a conversation with Makuu, who wishes to negotiate with the antelope. He explains that he and his float sleep during the dry season, and wish to do so near his watering hole. But he refuses to compromise and takes a strike at Makuu, with the crocodile striking back in retaliation. The Lion Guard arrives on the scene, and try to work out the situation by placing Beshte between the quarreling pair. As Makuu explains, Bupu attempts to strike him again, and Makuu retaliates again. Kion warns the crocodile, who slinks away, mentioning that he has no desire for a fight. Bupu is proud of himself, claiming that Makuu wouldn't try tangling with an antelope again.
Later, Bupu tries to negotiate with Makuu again at Pride Rock, but Kion pounces on Makuu, believing him to be starting another attack. When his father reveals the truth, Makuu refuses to continue since nobody will trust him. Simba assures Bupu that they will try again, but he too, refuses, claiming that negotiating is clearly not the crocodile way, before leaving the king and his son.
Later at the summit, Kion tells Bupu and the other leaders that Makuu has completed his journey through the Circle of Life after an accident involving him falling into a pit. Everyone is disappointed with Bupu stating that they "were so close to an agreement." But to their surprise, Makuu reveals himself to be fine once he found out that it was Vuruga Vuruga and Twiga who planned the trap. Bupu along with the others hold their breath in shock as Makuu mentions how badly he's been treated, causing them guilt. After Bupu grows tired of everyone's gasping, to everyone's relief, Makuu found the prank worthy of a crocodile. Finally able to trust Makuu, Bupu excitedly resumes negotiations allowing his float to sleep near his herd's watering hole. However, he butts heads with Vuruga Vuruga when she allows the crocodiles to sleep near their mud wallow, prompting Simba to step in.
After kicking Mzaha out of his herd, Fuli is tasked with taking him home, and speaks with Bupu. He is adamant that he doesn't want him back, and that they sent him away for a good reason. While Fuli agrees that he's a little different, she also mentions that he should be with his family. When Bupu still refuses, she adds 'please' to her words, and Bupu finally gives in. He calls to Mzaha that he's back with the herd, and the youngster reacts with joy. Fuli thanks Bupu, before quickly rushing away. After she leaves, Mzaha tries to play tag with a few herd members, much to Bupu's annoyance.
Later, Mzaha continues to disrupt his herd by trying to play tag while they're grazing. Bupu scolds the youngster, telling him that antelopes are not silly creatures and prompting Mzaha to leave the herd of his own accord. As he leaves, Bupu refers to him as a "silly creature".